Inflation apparatus



March 1, 1960 J. o. MARSH ETAL 2,926,836

. A INFLATION APPARATUS Filed April 29, 1957 1 l4 4 f IO 9 k\ \v LL A \m /7 5 LL /7 3 I I F/ G. a A! 4* 2,926,836 INFLATION APPARATUS John Oliver Marsh, Greenford, and Daniel Seed, Famborough, England, assignors to Specialties Development Corporation, Beileville, N.J., a corporation of New Jersey Application April 29, 1957,5erial No. 655,666

4 Claims. (Cl. 230-116) The present invention relates to inflation apparatus intended for the larger sizes of inflation bags, such as inflatable tents.

In our co-pending United States Patent No. 2,906,447, issued September 29, 1959, there is already described an inflation device comprising an axial flow turbine located with a multi-stage axial fan.

An inflation bag of the type referred to above may be required to be inflated very rapidly under emergency conditions, and for this purpose is inflated by release of gas from a supply of gas stored under pressure. The storage of gas under pressure involves not only the weight of the compressed gas itself but also the weight of the storage bottles.

The purpose of the inflation device described in the above mentioned patent is to utilise the energy of the gas stored under pressure to draw air into the inflation bag from the surrounding atmosphere, thus reducing the weight of the gas storage required to inflate the inflation bag.

The object of the present invention is to provide an alternative form of device to that described in our said co-pending patent application, the device of the present invention being simpler to manufacture and possibly of less weight than the device described previously.

According to the present invention an inflation device comprises a stationary body adapted to be secured in the wall of an inflation bag, an impulse turbine wheel mounted for rotation in said body, a centrifugal impeller driven by said turbine wheel, a valve arranged between the impeller and the turbine wheel and a gas jet nozzle adapted to direct gas from the high pressure supply onto the turbine wheel.

One construction of device made in accordance with the invention is hereinafter described with reference to the drawing, wherein:

Figure 1 is a section through the inflation device.

Figure 2 is a plan view of the centrifugal compressor portion of the device.

Figure 3 is a section through the turbine.

The apparatus comprises a turbine wheel 1 secured to a shaft 2, supported on bearings 3 in a turbine casing 4 which forms part of the stationary body structure of the device. The turbine wheel 1 is adapted to be driven by the impact of gas under pressure delivered through a jet nozzle 5 (see Figure 3) located in the casing 4, the nozzle 5 being connected by a pipe 6 to gas bottles or other high pressure gas supply (not shown).

The turbine unit thus described is supported by a back plate 7, which is in turn secured to the housing 8 of the centrifugal compressor. The housing 8 serves as the main support for the whole inflation device, as it is secured in the wall 9 of the inflation bag by means of a ring 10.

The impeller 11 of the centrifugal compressor is secured to the turbine wheel shaft 2 and has steeply raked ribs 12. The impeller 11 is positioned within the body 8 co-axially with an inlet aperture 14. The impeller 11 is dished and has a dish-shaped flexible valve member 15 secured to its rear face. The valve member 15 rests lightly against an annular rib 16 on the body 8 when United States Patent 0 2,926,836 Patented Mar. 1, 1960 there is no pressure built up in the inflation bag. When the impeller 11 is rotated at a suflicient rate, the pressure built up by it forces air past the valve member 15 into a diffuser comprising a plurality of blades 17. arranged between the body 8 and the back plate 7.

It will be appreciated that as soon as the impeller ,11 drops to a speed at which it is incapable of forcing further air past the valve 15, there will be a sharp closure of the valve by reason of the pressure differential on its two faces. The sharpness of cut-off will be augmented by a braking action on the rotor structure caused by partial engagement of the valve member with its seating, thus increasing the pressure difference between the two faces of the flexible valve member. The sharpness of valve cut-off prevents substantial leakage of gas back past the valve before it is fully closed.

We claim:

1. An inflation device comprising an impeller housing adapted to be secured in the wall of an inflation bag and having an outer surface arranged to be in communication with the ambient air and an inner surface arranged to be in communication with the air in the inflation bag, said impeller housing having an inlet aperture therein for ambient air, a turbine unit secured to said housing and adapted to be positioned within the inflation bag, said unit including a turbine Wheel and a shaft secured to said wheel and extending into said housing, a centrifugal impeller in said housing for entraining ambient air and secured to said shaft to be rotated by said turbine wheel, a valve operable by said impeller and positioned to provide a seal between said housing and the inflation bag when said' impeller is at rest and adapted to establish fluid flow communication between said aperture and the inflation bag through said housing when said impeller is driven at a predetermined rate, and conduit means extending through said impeller housing from said outer surface to said inner surface for directing a stream of gas under pressure against said turbine wheel to drive the: same and to inflate the bag together with the entrained ambient air.

2. An inflation device comprising an impeller housing adapted to be secured in the wall of an inflation bag, said impeller housing having an inlet aperture therein, a turbine casing secured to and spaced from the impeller housing, a shaft mounted in the casing, an end of the shaft projecting through the wall of the turbine casing, 21 turbine wheel carried on the shaft, a centrifugal impeller member secured to the projecting end of the turbine wheel shaft and positioned between the impeller housing and the turbine casing, the said impeller carrying a flexible valve disc on its rear face to seal against the impeller housing when the impeller is at rest, the turbine wheel being rotatable by means of a stream of gas under pressure directed onto it by a jet nozzle positioned close to it.

3. An inflation device according to claim 2, wherein the flexible disc is dished.

4. An inflation device according to claim 2, wherein the rear face of the impeller housing has a central area of a shape corresponding to the shape of the space swept by the impeller, a rib surrounding the central area to co-operate with the flexible valve disc and a series of curved diffuser blades arranged outwardly of the rib.

References Cited in the file of this patent UNITED STATES PATENTS 387,138 Bruce July 31, 1888 876,152 Douds Jan. 7, 1908 958,768 Richardson May 24, 1910 1,056,151 Coppus Mar. 18, 1913 1,182,665 Eynon et a1. May 9, I916 2,478,649 Wightman Aug. 9, 1949 2,777,632 Kishline et a1. Ian. 15, 1957 

